Mini tug mold cost estimation

Discussion in 'Boatbuilding' started by Simonas, Aug 29, 2017.

  1. Simonas
    Joined: Aug 2017
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    Location: Lithuania

    Simonas Junior Member

    Dear all,
    I'm building 11' mini tug from ply epoxy. I have an idea to build at least 5 for rent, and maybe more for sale. I came across an idea in this forum about molds. I have no experience with that, but very eager to learn. First newbie questions:
    1. How much would it cost to build a mold myself for mentioned boat?
    2. How much would it cost to build every hull from mold?
    3. How much time it takes to build a mold for first timer?
    4. Where I should get basic information about mold building, and building boats from mold?

    Thanks in advance, and please be patient, once You knew nothing about it too.
     
  2. Skyak
    Joined: Jul 2012
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    Location: United States

    Skyak Senior Member

    I can not answer any of your questions with certainty, but I am pretty sure nobody can and it will be a long time waiting.

    4. You get basic info on mold building and boat building from your material supplier. If suppliers don't want to talk to you, feel free to infer that they are not impressed with the future revenue your business should expect.

    Don't have any suppliers? Start poking around Professional BoatBuilder Magazine - Written for boatbuilders, repairers, designers, and surveyors http://www.proboat.com/ or ask in this site for specific products.

    3. 2. 1. Can not be answered without a design and some demonstration/quantification of skills. Nobody knows what $1 will buy in Lithuania, ask how many man hours it would take and add a factor for skill level. I would add that first timers rarely build molds.

    This is a nice honest blog about the creation of the tooling for the Dart sailboat -by a first time manufacturer that hired seasoned professionals from a town full of skilled builders; Blog Archive http://www.leftcoast.biz/iWeb/Left_Coast/Dart_tooling/Archive.html

    You say you will build from "ply epoxy" -does that mean that all surfaces are developable (conic surface)? If so then you should not need to build true molds. Instead you build "stitch and glue" over bulkheads and removable forms. A good designer can design a butterfly hull that can be assembled flat and popped into shape. Example: core sound 17
     
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Welcome to the forum.

    Amortizing the costs of a mold on 5 or even 10 hulls will be difficult to say the least. Molds are used for large production runs, not small ones, as you have envisioned.

    Mold costs are time, materials and intended durability related. A cheap mold isn't much more than a single hull's laminate schedule, but you'll likely cause a lot of damage to it, popping the first hull out, requiring repairs. A good mold, capable of many hull shell pulls will be several times the cost of a single hull's laminate schedule, but it'll last with minimum of repairs.

    Hull shell costs again are time and materials related, so you'd need a laminate schedule to evaluate costs.

    A novice, making his first mold is a long time project, if you want the end result to rival a factory build. It'll take longer to make the mold than the actual first hull.

    Given this is all new to you and you're interested in just a few hulls, forget about the mold. Build a few "one off hulls" and see how much you want to continue doing this sort of thing. I mention this because the margin on a limited production run is quite low (typically less than 10%), so not only aren't you going to get rich or even make a reasonable profit, it's hard, itchy work and very little room for screw ups and learning how to do it well.

    Lastly an 11' harbor tug has a very limited customer base to draw from and building the first from plywood with taped seams (my assumption) isn't the best set of shapes for a female 'glass mold, though is likely the cheapest and fastest way to get it done. The boats can be sheathed to help protect from abrasion and improve waterproofness.
     
    Last edited: Aug 30, 2017
  4. Simonas
    Joined: Aug 2017
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    Location: Lithuania

    Simonas Junior Member

    To clarify a bit, I'll try to post a picture.
    I thought it would be great design to startup with boatbuilding, because it's easy to build, and should be easy to sell.
    We live in a country with many lakes. Boat market is almost non existent, but still I believe I could sell 10 of these in 1-2 years. After it's done, I would like to start with bigger boats.
    I thought it would be faster/ better finish to build these tugs (5- 10 pieces) from mold, rather than ply/epoxy? Am I wrong?

    [​IMG]
     
  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    That's not an easy to build boat. Make a model and imagine bending plywood around those shapes in full size. Again, a mini tug is a very small market for a pleasure boat. You might want to reconsider your business models.
     
  6. Simonas
    Joined: Aug 2017
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    Simonas Junior Member

    Don't know how difficult, until made one. Designers says 280 hours. I expect to do it in 500.
    Talking about market, I don't know if there's any difference what to sell, when in my country is 2 dealerships, who are selling 10 boats each/ year. Total 20 new boats sold annually.
    Take a look, that's all new boats for sale in Lithuania:
    | Autoplius.lt https://en.autoplius.lt/ads/water-transport/motorboats?condition_id=23943&sell_price_from=3500

    I'm very open if You would have any suggestions for business model, which would be better.
    Thanks.
     
  7. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Do the math. let's say you're correct and you'll take 500 hours to build the boat. Multiply this number by what you'd like to make per hour. $20 per hour, means you have $10,000 in labor costs alone, per unit. Add materials, overhead, etc. and this figure will jump considerably (double, triple, quadruple, etc.). Next look at the prospective sales for a limited production run, on a handful of boats, so you can work out your margins. It doesn't take a rocket scientist to figure out where this is going.
     
  8. Simonas
    Joined: Aug 2017
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    Simonas Junior Member

    We've drifted quite heavily from the topic. Let's get back to it.
    So looking at the drawing is it possible to make a mold for such a tug?
     
  9. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    That hull can't be made from a single mould.
     
  10. Simonas
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    Simonas Junior Member

    What do You mean? I understand, that I need another mold for cabin.
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

    It won't pull out of a mould, it will be stuck in there. You will need a split mould.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    The sides look vertical, even without the back-slope at the stern, it would not draw out of your mould.
     
  13. Simonas
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    Simonas Junior Member

    That's very intelligent insight. I can't believe I didn't see it before. Thanks.
     
  14. Mr Efficiency
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    Mr Efficiency Senior Member

    Just not a mouldable thing as it stands, to retain the tugboat look simply not possible with a one-piece hull mould. Obviously it is designed to plane, and seeing standing in the little cabin would be impossible, avoiding anything more than a slight chop would be mandatory.
     

  15. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    Cost for the mold, plug or part.

    A 1/8" thick fiberglass laminate weighs about 1 lb per square foot.

    Calculate the total square feet of the item (mold, plug or part) being made and multiply it by the number of 1/8th thicknesses' 1"= 8, so 8lbs per square foot.

    About 30% of this will be glass, 70% resin.

    A plug might be 1/4" thick, so 2lbs per square foot.

    The mold will be in the 1/2" range or a bit more, it just depends on your methods. So at least 4 lbs per square ft.

    Gel coat will cover about 80 square ft per gallon.

    This does not include waste, which can add up quickly.

    While this isn't exact, it's very close. I have a spread sheet somewhere that goes into great detail on every product you plan to use, then you enter the cost for each product and it gives you the total bill of materials to build a plug, mold or part.

    This is for hand lamination, which is what you'll be doing, other methods use a different resin to glass ratio.

    We don't know the cost or availably of the resin and glass in your area, you'll need to find this out locally.
     
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